Mono-frequency sound source



Sept. 20, 1966 J. J. HILL 3,273,530

MONO-FREQUENCY SOUND SOURCE Filed Aug. 2, 1965 1 N VENTOR.

JAMES J. HILL United States Patent 3,273,530 MONO-FREQUENCY SOUND SOURCE James J. Hill, 3750 E. 10 Court, Hialeah, Fla. Filed Aug. 2, 1965, Ser. No. 476,350 1 Claim. (Cl. 116-137) This invention relates in general to sound generators and more particularly to a manually excited mono-frequency sound source for signaling purposes.

A principal object of the present invention is the provision of a directional mono-frequency sound source responsive to manual push button operation for transmitting a sound signal of predetermined frequency into a microphone for ope-rating a tuned responsive device over a standard communication channel.

Another object of the invention is the provision of a tuning fork constructed to resonate at a predetermined fundamental frequency and housed within a casing for directing the sound waves in a predetermined direction including a push button means for manually energizing the tuning fork.

A further object of the invention is the provision of a manually operated mono-frequency sound source in which a pawl operated striker for momentarily impacting a resonant member is tuned to a predetermined frequency when said trigger means is manually operated.

These and other objects and advantages in one embodiment of the invention are described and shown in the following specification and drawing, in which:

FIG. 1 is a perspective view of the sound device.

FIG. 2 is a front elevation of the device shown in FIG. 1 with cover removed.

FIG. 3 is a cross sectional end elevation taken through section line 3-3, FIG. 2.

FIG. 4 is a fragmentary .view, the same as that shown in FIG. 2, in changed position.

FIG. 5 is an enlarged perspective view of elements shown in FIG. 2.

Referring to FIG. 1, the sound generating device is contained within a casing 1 having five sides, preferably made from molded plastic material and dimensioned to be convenient-1y held in the hand. A foraminated cover 2 substantially transparent to sound waves is secured to the open side of casing 1, as shown. A push button 3 is slidably positioned for movement through the side of casing 1 by a metal grommet 4 with the button positioned for conventional operation by the thumb.

All of the working elements of the device are mounted on a chassis or base 5 formed by die means and secured to the inside wall of easing 1 by adhesive or other well known means, not shown. Referring to FIGS. 2, 3, and 4, a tuning fork 6 having integral parallel bars 77 is secured by the end thereof by screws 88 through an upturned end 9 of base 5, as shown in FIG. 4.

Referring to FIG. 2, a striker spring 10 is secured to an upturned ear 11 of base 5 by rivets 12, as shown, with a striker 13 secured in the outer end portion of spring 10 by a screw 14.

Although tuning forks having a wide range of different frequencies may be used, in this embodiment, a fork having a fundamental frequency of approximately one thousand cycles per second has been selected. The striker spring 10 is selected to have a natural resonant frequency substantially different than the fork 6 in order that beat note frequencies between the fork are substantially different than the fundamental frequency of the fork or the first order of harmonics thereof.

The striker is actuated by mechanism, better shown in FIG. 5, which includes a slider 15 retained on base 5 for reciprocation by shoulder rivets 16 secured in base 5 through a slot 17 in the slider. The slider terminates at one end in a formed projection 18 for frictionally retaining the button 3 which may be further secured by an adhesive, not shown. A coil spring 19 is secured at one end by an car 20 integral with an off-set from base 5. The opposite end of spring 19 is secured in an integral projection 21 of slide 15. A pawl member 22 is secured for oscillation on base 5 by shoulder rivet 23 and includes a downward formed stop 24 for limiting the counter clockwise movement of the pawl and a release-restore projection 25 extends from pawl 22, as shown, and is positioned to abut pin 26 secured in base Sand also against upstanding release abutment 27 formed in base 5, when slide 15 is moved through its full range.

An upstanding sear projection 28 integral with pawl 22 is adapted to move substantially normal to spring 10 and positioned to momentarily engage the outer end thereof and flex spring 10 to the posit-ion shown in FIG. 4. When the slide is moved slightly beyond this position, the sear will disengage from the end of the spring 10 and the resulting restoration of the spring will permit the striker 13 to strike the left bar 7 of fork 6 one impact and then rapidly assume the idle position shown in FIG. 2.

The disengagement of the sear 24 from the end of the spring results from the engagement of projection 25 with abutment 27. When the button 3 is released, spring 19 will return slide 15 to its initial position, shown in FIG. 5, and concurrently pin 26 in base 5 will engage projection 25 and restore the pawl 22 to its initial idle position with the stop 24 hearing against the side of the slide 15, as shown in FIG. 5. Excess inner movement of the slide is prevented by an upstanding stop 29 formed in base 5 for limiting the stroke of slide 15 when moved by button 3.

Referring to FIG. 2, the outer end of cover 2 is intended to seat against shoulder 30 around the inside of casing 1 and be secured thereto by an adhesive, not shown.

In operation and when in idle position, the elements of the device are ,in the position shown in FIG. 2 with the tuning fork free to resonate in normal manner.

When the device is held in the hand and the button 3 depressed, slide 15 will move laterally on the base against the restraining action of spring 19 and the projection 25 will move away from pin 26 and permit the sear projection 28 to engage and flex striker spring 10 through a prede termined range and subsequently release same, permitting the striker to impact the adjacent bar 7 of the tuning fork one time, thus exciting both bars of the tuning fork 6 into resonant vibration for a short period of time, which will emit a predetermined mono-frequency sound'wave through the cover 2 of sufiicient duration for direction into a microphone or other sound responsive devices for a variety of uses.

It is understood that certain modifications in the construction, utilizing the features above described, are intended to come Within the scope of the appended claim.

Having described my invention, I claim:

A manually operated mono-frequency sound source comprising a means forming a base,

a tuning fork parallel with and secured to said base for resonance at a predetermined audio frequency,

a flat striker spring secured at one end thereof to said base and positioned in parallel relation to said fork including a striker member secured in the opposite end portion thereof and positioned in predetermined spaced relation from said fork when said striker spring is in its idle position,

an operating member slidably retained on said base for reciprocation transverse said fork from an idle to an activated position,

a push button secured on one end of said member,

spring means biased between said base and said memher for urging the latter into said idle position,

operating a pawl means pivotally secured for a limited range of oscillation on said operating member including an integral tripping projection,

an abutment integral with said base positioned in the path of movement of said tripping projection when said operating member is moved to its said activated position,

a stop projection in said base in the path of return movement of said tripping projection of said pawl means for restoring the latter to its initial position when said operating member is moved to its idle position,

a sear projection integral with said pawl means for momentarily engaging and disengaging the opposite said end of said striker spring when said operating member is moved to its said activated position and said pawl means is rotated by engagement with said abutment whereby said striker spring will flex and impact said striker member against said fork for oscillating the latter at its fundamental frequency when said push button is operated,

a cover casing secured to said base constructed to be held in the hand with one side thereof substantially transparent to sound and including an aperture through said casing for the free operation of said button by a finger of the hand.

References Cited by the Examiner UNITED STATES PATENTS 5,164 6/1847 Hill et a1. 84-409 1,419,919 6/1922 Deagan 84-409 1,560,056 11/1925 Horton 58-23 X 1,807,010 5/1931 Ranger 84-409 2,263,106 11/1941 Sebouh 84-409 3,106,124 10/1963 Asten 84-409 3,165,090 1/1965 Smith 116-137 3,183,509 5/1965 Ellett 116-137 FOREIGN PATENTS 201,679 9/1908 Germany.

LOUIS J. CAPOZI, Primary Examiner. 

